Abstract：Based on two-dimensional vector sum method(VSM)，the determination of the whole sliding direction of slope with 3D vector sum method is put forward；and initial sliding direction can be obtained by current stress state. Then the whole sliding direction and the factor of safety with this method is solved. This method is used in several 3D examples；and the results demonstrate that the factors of safety are in good agreement with that of the limit equilibrium method，and the results are not sensitive to element sizes of the slip surfaces. Finally，this new method is applied to the foundation stability analysis of dam section No.26 in the Three Gorges Project. Four slip paths designated through detailed investigation are analyzed with the plane vector sum method and the 3D vector sum method. The calculating results with the 3D vector sum method show that the factors of safety with the 3D vector sum method are larger than that with the 2D method；and the factor of safety of the deep slip paths is larger than the shallow ones，greater than 1.0. Therefore，the dam section No.26 under the current loads in the Three Gorges Project is safe. This new method is clear in physics and mechanics，and only one time elastic calculation or elastoplastic calculation，and the 3D factor of safety of potential sliding mass can be achieved without too many artificial assumptions. The process of this new analysis method is simple and easy to use in practical engineering projects.
郭明伟，葛修润，李春光，王水林，邓琴. 边坡和坝基抗滑稳定分析的三维矢量和法及其工程应用[J]. 岩石力学与工程学报, 2010, 29(01): 8-20.
GUO Mingwei，GE Xiurun，LI Chunguang，WANG Shuilin，DENG Qin. THREE-DIMENSIONAL VECTOR SUM METHOD EMPLOYED IN SLOPE AND DAM FOUNDATION STABILITY ANALYSES AND ITS APPLICATIONS TO PRACTICAL ENGINEERING. , 2010, 29(01): 8-20.
